U.S. patent number 4,229,081 [Application Number 05/919,182] was granted by the patent office on 1980-10-21 for electro-mechanical image converter.
This patent grant is currently assigned to The United States of America as represented by the Secretary of the Army. Invention is credited to Terry L. Jones, Brian S. Miller.
United States Patent |
4,229,081 |
Jones , et al. |
October 21, 1980 |
Electro-mechanical image converter
Abstract
A two-dimensional array of small, thin, flexible, metalized
mirrors are mted atop supports on one side of a photoelectric
layer. A visible light or infrared image on the other side of the
layer induces an electron image (charge pattern) beneath the
mirrors. The mirrors deflect towards the layer in accordance with
the charge pattern. Light projected onto the mirrors is reflected
and forms an image dependent on the deflections thereof.
Inventors: |
Jones; Terry L. (Springfield,
VA), Miller; Brian S. (Alexandria, VA) |
Assignee: |
The United States of America as
represented by the Secretary of the Army (Washington,
DC)
|
Family
ID: |
25441658 |
Appl.
No.: |
05/919,182 |
Filed: |
June 26, 1978 |
Current U.S.
Class: |
359/292;
250/330 |
Current CPC
Class: |
H01J
29/12 (20130101) |
Current International
Class: |
H01J
29/10 (20060101); H01J 29/12 (20060101); H01J
029/70 () |
Field of
Search: |
;350/266,269,285,359,360,361 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Sikes; William L.
Attorney, Agent or Firm: Edelberg; Nathan Gibson; Robert P.
Dunn; Aubrey J.
Government Interests
The invention described herein may be manufactured, used, and
licensed by the U.S. Government for governmental purposes without
the payment of any royalties thereon.
Claims
We claim:
1. An electro-mechanical image converter including:
a photoelectric layer having essentially planer and parallel
photon-image and electron-image sides;
an array of deformable, light-reflective elements on said
electron-image side of said photoelectric layer, wherein said
elements each include an insulating support with one end on said
electron-image side of said layer and with at least a thin metallic
leaf on the other end;
means for establishing a voltage potential between said layer and
said array and whereby a photon image on the photon-image layer
induces an electron image on the photon-image side thereof and
further whereby said elements deflect toward said electron-image
side of said layer in accordance with the electron image
thereon;
a light source;
means for projecting said light from said light source onto said
elements and for forming an image of light reflected therefrom;
and
means for reversing said voltage potential whereby said elements of
said array return to their undeflected positions.
Description
BACKGROUND OF THE INVENTION
This invention is in the field of image converters, and
particularly those converters for producing visible images from
lower level visible images (image intensifiers) or from infrared
images. Such converters usually include photo-electric layers
having low level visible or infrared image sides and electron image
side. The electron image (charge patterns) may be intensified by
such means as microchannel plates. In any event, electrons are
eventually used to bombard and excite a phosphor to produce a
visible image. The problem with such converters is that it is
difficult in practice to obtain high brightness and high contrast
visible images. Such images are necessary if one desires to
directly view or to project an image onto a screen or the like. Our
invention is able to produce an image capable of being directly
viewed or projected but not depending upon a phosphor to produce an
image. Instead of a phosphor we incorporate into our invention a
light valve projection system as shown in U.S. Pat. Nos. 3,746,911
and 3,886,310. Another system using the equivalent of light valves
is that shown in U.S. Pat. No. 3,667,830.
SUMMARY OF THE INVENTION
Our invention is an electro-mechanical image converter including a
photo-electric layer for producing an electron image (charge
pattern) from a photon image. On the charge pattern side of the
layer we have an array of small metalized light reflectors. Each
reflector is flexible and bends toward the layer in accordance with
the charge on the layer beneath the reflector. Light projected onto
the array is reflected and formed into an image dependent on the
charge pattern of the photoelectric layer.
BRIEF DESCRIPTION OF THE DRAWINGS
The single drawing FIGURE is a schematic showing of the
invention.
DETAILED DESCRIPTION OF THE INVENTION
The invention may perhaps be best understood by referring to the
drawing, in which element 10 is a photoelectric layer of p-type
silicon. On one side of 10 is objective lens 11 for forming an
image of a far infrared or low-level visible scene onto 10. This
image may be called a photon image. On the opposite side of 10 is a
light-valve array consisting of parallel reflector assemblies 12
carried by insulating walls 13. Layer 10 responds to photon images
thereon to produce an electron image (charge pattern) beneath the
reflector assemblies. Each reflector assembly is metalized plastic
or the equivalent and includes a stem 12a and leaves 12b on either
side of the stem. One end of each 12a is connected to a common
conductor 14. Layer 10 has ohmic contact 15 on its edge.
A readout means 16 has electrical conductors connected to conductor
14 and contact 15. This readout means, as an example, may include
multivibrator 17, delay line (or equivalent) 18, relay 19, and
power source 10. Relay 19 includes double-pole, double-throw
contacts 19a/19b. The output of multivibrator 17 feeds both delay
line 18 and light source 21 with reflector 22. Lenses 23 and 24
serve as projection lenses for light emitted by source 21 and
reflected from reflector assemblies 12. An electron image on layer
10 can be produced as a visible image on screen 25, as will be
explained below
OPERATION
As mentioned above, a photon image on one side of 10 will induce a
charge pattern on the other side. With the contacts of relay 19 as
shown, battery 20 will apply a potential to reflector assemblies
12. This potential causes an individual reflector leaf 12b to
deflect toward 10 in accordance with the charge beneath that leaf.
The leaves will thus be deflected in a pattern dependent upon the
photon image on 10. This pattern may be used to produce a visible
image on screen 25 by way of light 21.
When multivibrator 17 produces an output pulse, light 21 is turned
on and floods the array of reflector assemblies 12 with a short
read pulse of visible light. For undeflected leaves 12b, this light
is merely reflected back to 21. However, for deflected leaves, the
light will pass back through lens 23 to lens 24 and thence to
screen 25 in the manner as taught in U.S. Pat. No. 3,886,310.
Screen 25 will thus show an image representative of the input
photon image on layer 10. Alternately, lens 24 may be an eyepiece
for direct viewing. The output pulse from 17, after delay through
delay line 18 will cause contacts 19a/19b of relay 19 to operate to
their alternate positions and to reverse the potential between 10
and the reflector array. This reversal effectively erases the
electron image on 10 and resets 10 for a new image.
Although we have described as specific contents for our readout
means 16, obviously other elements are capable of performing the
same functions, the only requirements being a read pulse and a
reset pulse. If desired, 21 may be pulsed at a television or other
frame rate to provide a real-time moving image or at a much slower
rate to provide image integration. Moreover, delay 18 may not be
needed if the read pulse (and erase pulse) are of sufficient
shortness with respect to the response time of the leaves.
Moreover, readout of the electron image may be accomplished in an
entirely different manner from that so far disclosed. Specifically,
for light 21 we may substitute a pulsed laser or other light
capable of providing a narrow beam. This beam may be swept in a
raster pattern as it is pulsed, to fall on only reflective leaves
12b. Also, the beam may be swept and pulsed at rates compatable
with television rates, if desired. It can also be used as an input
channel for other than uniform illumination to modify the output
image by an additional information source.
The particular shapes of individual leaves 12b is not critical, nor
is the orientation of reflector assemblies 12. However, reflector
22 must have a shape and orientation corresponding to any
particular leaf shape and assembly orientation. Moreover, although
the leaves have been described as metalized plastic, they may be
made of metal, but with a reduced life expectancy, since metals do
not have the long-term elasticities of long chain polymers such as
plastics. If necessary, the response time of the leaves may be
lengthened with a film of dielectric liquid, such as water.
Layer 10, although described as being p-type silicon, may also be
n-type, with battery 20 reversed from the connection shown. As a
matter of fact, 10 may be chosen from any of those materials having
an appropriate band-gap for the wavelength of interest. The
materials include p and n-type germanium, lead tin telluride,
etc.
* * * * *